GE Freeze Up

[qtband]

GSS25LGMA
The freezer is frosting up and not freezing anymore. 
I replaced the defroster and the thermostat, but I still have the problem.
Any ideas???
qtband

[Koi Guy]

By 'frosting up' I assume you mean having an automatic defrost issue- frost/ice buildup on evaporator coil, top to bottom, left to right, and front to rear.

There are five possible issues that would cause this. 1) Failed (broken) heat element. 2) Failed (broken) defrost terminator. 3) Failed (open or out of range) thermistor. 4) Failed control board (failure to iniate defrost cycle, defrost relay inoperable). 5) Broken wire in cabinet.

Since you have replaced the heat element and defrost terminator we will exclude those.

The thermistor is what monitors the temperature at the top of the evaporator coil. It can fail and the board 'thinks' the coil is warm. So the board will go into defrost, but instantly recognize that the coil is warm and not provide voltage to the heater. If the thermistor has black rubber where the wires connect to the thermistor, it has been known to fail out of range. (GE used a few different manufacturers for these and the ones with the black rubber are least robust.) Thermistors are cheap and easy to replace. It is located on the top of the evap coil.

The board is located on the back of the unit. It has a defrost relay that will close (providing power) to the heat element when it determines a defrost is needed. It is possible that the board has failed and is either not iniating a defrost cycle, or, it is initiating a defrost cycle but the defrost relay has failed.

Lastly, I have seen the wiring break in the cabinent (non serviceable) from the board to the heat element. (Very rare though).As a test, you can unplug the power cord from wall. Remove the connector that supplies power to the board located on bottom of board, three wires. Look at the board closely where the connector was removed and you will see Comp, Defrost, Line. You can use a jumper wire (piece of wire 2-3" striped on the ends) and 'jump' the Line and Defrost by inserting wire into the connector. Plug in power cord. You are now providing known power to the heat element and it should begin to heat. This indicates that you do not have a broken wire (as well as a quick way to defrost the coil.) It also indicates that you have a working defrost limiter (provided the coil is still iced up), as well as indicates a working heater. It does not, however, indicate either a failed thermistor nor a failed board.

Unfortunately you replaced the two components that are easily tested to see if they are failed. The rest of the components require a bit more testing and although possible to test the thermistor, they can be good when tested, but fail within a certain range, whcih can be tricky.

My standard protocol for this is to test the heater and defrost terminator using a multimeter and checking for simple continuity. If they are good, no need to replace them. If they are good, I then test for a broken wire using the jumper. If I get heat, then I know I have either a failed board or a failed thermistor. Since the thermistor is cheap, I replace the board and thermistor if I have a defrost issue. Often it is simply the board, but since I am already in the compartment, it is cheap and easy enough to replace the thermistor while I am in there, rather than have a call back.

Good luck...

[qtband]

Thanks for the info.  I ordered 2 thermistors to see if that works.  The board is about $250!  Hope it's not that.

 

[16345Ed]

Likely the board on this one... although you are following proper protocol by replacing thermistors. 

Let us know how you make out. 

[qtband]

The freezer was still freezing up so I replaced the temperature sensors.  It's been a week and I don't see any frost.  I'm hoping this works.

Fingers crossed!

[qtband]

UPDATE:  No frost yet.  It's been 3 weeks.  Looks like the cheapest part was the solution.  Thanks everyone.

[qtband]

Once again, spoke to soon.   It froze up again so i replaced the board.  Looks like the most expensive part was the culprit...